Ap rengar, Plz help

I've been recently trying AP Rengar jungle using the new runeglaive thing and it's been going very well. It can burst down whole teams because of Runglaives AOE spellblade, the one situation is it doesn't burst down enough. In a recent game i rushed in and left 2 champions on their team with less than 100 health and died right after. Any thoughts on how i could improve? I am after to keep runglaive for the AOE burst. Currently i build (simple order cuz i play this for fun) trailblazer, Runeglave, Ludens, Sorcerers, Furor, Nashors, Hextech GunBlade, Spirit Visage (never made it up to spirit visage).